Inhibition of Mir-21-5p Affects the Expression of LNCRNA X-Inactive Specific Transcript and Induces Apoptosis in MCF-7 Breast Cancer Cells

Samaneh Nejaddehghan; Seyed Jalal Zargar; Mana Oloomi; Kazem Baesi; Morteza Kouhsar

doi:10.18502/ijph.v53i3.15154

Inhibition of Mir-21-5p Affects the Expression of LNCRNA X-Inactive Specific Transcript and Induces Apoptosis in MCF-7 Breast Cancer Cells

Iran J Public Health. 2024 Mar;53(3):714-725. doi: 10.18502/ijph.v53i3.15154.

Authors

Samaneh Nejaddehghan¹, Seyed Jalal Zargar¹, Mana Oloomi², Kazem Baesi³, Morteza Kouhsar⁴

Affiliations

¹ Department of Cell and Molecular Biology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
² Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran.
³ Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran.
⁴ Laboratory of Systems Biology and Bioinformatics (IBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran.

Abstract

Background: We aimed to investigate miR-21-5p inhibition effect on lncRNA-XIST expression and apoptosis status of MCF-7 cells.

Methods: The MCF-7 cells were cultured and transfected by the anti-miR-21-5p oligonucleotide and expression of miR-21-5p, lncRNA-XIST, apoptosis-associated genes (bax and p53) and one miR-21-5p-unrelated lncRNA (BC200) was assessed by RT-qPCR. Furthermore, cell viability checked by MTT assay and apoptosis and cell cycle in transfected cells were detected by flow cytometry. Also, bioinformatics analysis on the transcriptome data confirmed that the lncRNA XIST might have a critical role in breast cancer (BC) cell apoptosis through ceRNAs mechanism and possible regulatory interactions with miR-21-5p.

Results: Expression of miR-21-5p and lncRNA-XIST was significantly down- and up-regulated respectively (P<0.05). However, there was no significant change in lncRNA-BC200 expression. Also, the expression of bax and p53 upraised significantly (P<0.05). In transfected cells, MTT and flow cytometry assays reported a highly significant decrease and increase in viability and apoptosis respectively.

Conclusion: Inhibition of miR-21-5p resulted in significant upregulation of lncRNA-XIST and apoptosis-associated genes bax and p53, which led to the induction of apoptosis in MCF-7 cells. Therefore, more investigations may provide a valuable target for studies on molecular therapies for BC.

Keywords: Apoptosis; Breast cancer; Non-coding RNA; X-inactive specific transcript.